Molecular characterization and genotyping of isolates from cancer patients with infection or asymptomatic colonization.

Cancer patients with infection (CDI) are at a higher risk for adverse outcomes. In addition, a high prevalence of asymptomatic colonization (CDAC) has been reported in this vulnerable population. The molecular characteristics and potential role of CDAC in healthcare-related transmission in the cancer population have been poorly explored. We aimed to compare the molecular and genotypic characteristics of isolates from cancer patients with CDAC and CDI. We conducted a prospective cohort study of cancer patients with CDAC or CDI from a referral centre. Molecular characterization, typification and gene expression of isolates were performed. The hospital-onset and community-onset healthcare facility-associated CDI rates were 4.5 cases/10 000 patient-days and 1.4 cases/1 000 admissions during the study period. Fifty-one strains were isolated: 37 (72 %) and 14 (28 %) from patients with CDI or CDAC, respectively. All isolates from symptomatic patients were , and four (10 %) were . In the CDAC group, 10 (71 %) isolates were toxigenic, and none were +. The Δ18 in-frame deletion and two transition mutations were found in five isolates. After bacterial typing, 60 % of toxigenic isolates from asymptomatic carriers were clonal to those from patients with -associated diarrhoea. No NAP1/027/BI strains were detected. We found a clonal association between isolates from patients with CDAC and CDI. Studies are needed to evaluate the potential role of asymptomatic carriers in the dynamics of nosocomial transmission to support infection control measures and reduce the burden of CDI in high-risk groups.